The present invention generally relates to drilling equipment, and more particularly to a drilling apparatus capable of having a minimal axial length to permit its use within limited confines.
The axial length of a drilling apparatus along the axis of its drill bit can at times exceed the space available for some drilling applications. For example, the inlet pipes of steam turbine nozzle boxes may be on the order of about six inches (about 15 cm), which severely limits the size of the drilling equipment that can be placed between inlet pipe pairs for the purpose of drilling holes in their opposing parallel faces. While various small pneumatic, hydraulic and electric drills have been developed that are sufficiently small to fit between steam turbine inlet pipes, they typically lack the power, speed and/or thrust force required to accomplish the drilling operation due to the hardness of the inlet pipe material.